<!DOCTYPE html>
<html lang="en">
<head>
    <meta charset="UTF-8">
    <title>css实现圆环</title>
    <style>
        div{
            width:150px;
            height:150px;
            border-radius: 50%;
            background-color:red;
            border:10px solid;
            padding:15px;
            background-clip: content-box;
        }
    </style>
</head>
<body>
<div></div>
</body>
</html>